The number of women imprisoned in the United Kingdom is rising rapidly, but there is little research on their health and well-being. We could find no studies in which the researchers had used measures of subjective health status to gain a picture of the health of imprisoned women. This self-completed questionnaire study aimed to explore the usefulness of the Short Form 36 (SF-36) in a general female prison population. The scores of imprisoned women for all but 3 of the 8 dimensions were significantly lower than those for women in the social class with the worst health in the United Kingdom, confirming the very poor mental and physical health of this population.